raid 0 vs raid 0 + 1 whch is better.
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raid 0 vs raid 0 + 1 whch is better.
never used raid before so just asking which is best for chess.
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Re: raid 0 vs raid 0 + 1 whch is better.
Neither is very interesting for chess. The only time disk matters is for tablebase access, and neither raid gives much advantage there.
Note that raid0+1 prevents you from losing data in case a disk fails at the cost of half the drives.
But for chess it's completely irrelevant.
Note that raid0+1 prevents you from losing data in case a disk fails at the cost of half the drives.
But for chess it's completely irrelevant.
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Re: raid 0 vs raid 0 + 1 whch is better.
Totaly agreed here and that's why I'd never given extra money to build raid systems....Gian-Carlo Pascutto wrote:Neither is very interesting for chess. The only time disk matters is for tablebase access, and neither raid gives much advantage there.
Note that raid0+1 prevents you from losing data in case a disk fails at the cost of half the drives.
But for chess it's completely irrelevant.
_No one can hit as hard as life.But it ain’t about how hard you can hit.It’s about how hard you can get hit and keep moving forward.How much you can take and keep moving forward….
Re: raid 0 vs raid 0 + 1 whch is better.
Depends on how many drives - RAID 0 does give faster tablebase access, but you are way better off just using 5-men on a fast 8GB flash drive.
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Re: raid 0 vs raid 0 + 1 whch is better.
raid 0 (striping). But only if you have good I/O (SCSI devices primarily).seemychess wrote:never used raid before so just asking which is best for chess.
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Re: raid 0 vs raid 0 + 1 whch is better.
Raid 0 is far faster, because you can do parallel reads to read in one chunk of an EGTB file. This is how I use them on my office box. When Eugene and I first started testing blocksizes for compression, there were several things we considered, and testing on raid 0 was one of them and with good SCSI controllers, it was a big win.Gian-Carlo Pascutto wrote:Neither is very interesting for chess. The only time disk matters is for tablebase access, and neither raid gives much advantage there.
Note that raid0+1 prevents you from losing data in case a disk fails at the cost of half the drives.
But for chess it's completely irrelevant.
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Re: raid 0 vs raid 0 + 1 whch is better.
Is it really the block read time that limits things? I'd expect it to be the access latency by far. I don't see how access latency would improve from RAID-0.bob wrote: Raid 0 is far faster, because you can do parallel reads to read in one chunk of an EGTB file. This is how I use them on my office box. When Eugene and I first started testing blocksizes for compression, there were several things we considered, and testing on raid 0 was one of them and with good SCSI controllers, it was a big win.
Perhaps it's less if you have 15000 rpm SCSI drives.
Edit: One thing that WOULD improve is engine startup time. It can be a pain with 6-men...for that both RAID-0 and RAID0+1 would indeed be faster.
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Re: raid 0 vs raid 0 + 1 whch is better.
raid-0 is blindingly fast for that as well. But when you start reading big blocks of compressed data, bandwidth becomes an issue as well. When I can set it up again, I can run a test using a single 15K scsi drive, and then a raid-0 set of the same drives. When I tested this last, it made a significant difference. Latency is an issue, particularly on the slower drives. But bandwidth is right in there as well. The other advantage is that the average seek distance is about 1/4 of what it is on one drive, when you use 4 drives with raid-0 so it also drives down the seek-time as well... I've tried it on SATA drives and they suck at this so there is not much of an advantage there other than a little savings on seek time, and a tad of help on latency since an RPS controller can choose which stripe of the data to read first to optimize the multiple latencies across the drives.Gian-Carlo Pascutto wrote:Is it really the block read time that limits things? I'd expect it to be the access latency by far. I don't see how access latency would improve from RAID-0.bob wrote: Raid 0 is far faster, because you can do parallel reads to read in one chunk of an EGTB file. This is how I use them on my office box. When Eugene and I first started testing blocksizes for compression, there were several things we considered, and testing on raid 0 was one of them and with good SCSI controllers, it was a big win.
Perhaps it's less if you have 15000 rpm SCSI drives.
Edit: One thing that WOULD improve is engine startup time. It can be a pain with 6-men...for that both RAID-0 and RAID0+1 would indeed be faster.
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Re: raid 0 vs raid 0 + 1 whch is better.
Well RAID 0 on SATA II SSD drives (especially the latest ones) is the best of both worlds. Excellent latency with good bandwidth.
RAID 0 is usually designed for an application where speed is critical. Say if you have 2 drives in RAID 0 and you lose one ... then all you data is gone.
RAID 1 is usually designed for an application where data integrity is critical. So if you have 2 drives in RAID 1 and you lose one ... you can rebuild your data by simply installing a new drive. Basically it mirrors the data on both drives which also give you half the amount of available data storage. You do get better performance than a single drive due to the data being placed in 2 locations instead of one but not as high performance as RAID 0.
Obviously you are not confined to 2 drives in a raid array and big raid arrays can easily be the most expensive item in a system.
RAID 0 is usually designed for an application where speed is critical. Say if you have 2 drives in RAID 0 and you lose one ... then all you data is gone.
RAID 1 is usually designed for an application where data integrity is critical. So if you have 2 drives in RAID 1 and you lose one ... you can rebuild your data by simply installing a new drive. Basically it mirrors the data on both drives which also give you half the amount of available data storage. You do get better performance than a single drive due to the data being placed in 2 locations instead of one but not as high performance as RAID 0.
Obviously you are not confined to 2 drives in a raid array and big raid arrays can easily be the most expensive item in a system.
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Re: raid 0 vs raid 0 + 1 whch is better.
I don't see how you get any better performance at all on raid-1. You have a primary drive and a secondary (mirror) drive. How is the second drive going to help the speed of accessing data from the primary drive?M ANSARI wrote:Well RAID 0 on SATA II SSD drives (especially the latest ones) is the best of both worlds. Excellent latency with good bandwidth.
RAID 0 is usually designed for an application where speed is critical. Say if you have 2 drives in RAID 0 and you lose one ... then all you data is gone.
RAID 1 is usually designed for an application where data integrity is critical. So if you have 2 drives in RAID 1 and you lose one ... you can rebuild your data by simply installing a new drive. Basically it mirrors the data on both drives which also give you half the amount of available data storage. You do get better performance than a single drive due to the data being placed in 2 locations instead of one but not as high performance as RAID 0.
Obviously you are not confined to 2 drives in a raid array and big raid arrays can easily be the most expensive item in a system.
One can also use raid-5 and get both a speed boost because of the striping, plus reliability because of the redundant data written on one drive. But it isn't as fast as raid-0 for egtbs and I don't care about reliability as I will just copy them back after replacing the drive anyway, the data is not critical because it can be restored.